1. Field of the Invention
The invention generally relates to force measurement systems. More particularly, the invention relates to a force measurement assembly with damping and a force measurement system including the same.
2. Background and Description of Related Art
Force measurement systems are utilized in various fields to quantify the reaction forces and moments exchanged between a body and support surface. For example, in biomedical applications, force measurement systems are used for gait analysis, assessing balance and mobility, evaluating sports performance, and assessing ergonomics. In order to quantify the forces and moments resulting from the body disposed thereon, the force measurement system includes some type of force measurement device. Depending on the particular application, the force measurement device may take the form of a balance plate, force plate, jump plate, an instrumented treadmill, or some other device that is capable of quantifying the forces and moments exchanged between the body and the support surface.
Force measurement systems are typically mounted inside a room within a building. Due their high degree of measurement sensitivity, the accuracy of the output generated by these measurement systems is often adversely affected by vibrations imparted thereon by the building structure. These vibrations may be caused by mechanical equipment within the building, such as pumps, fans, and chillers, or alternatively, may be caused by external forces acting on the building structure, such as those caused by wind forces or nearby roadways. As such, the measurement accuracy of these highly sensitive measurement instruments is unnecessarily compromised by building vibrations. Also, when force measurement systems are mounted on uneven surfaces or surfaces with undulations, the resulting instability of the measurement instrument often leads to measurement errors (i.e., resulting from the rocking of the measurement instrument). In addition, when force measurement systems are affixedly attached to mounting surfaces that undergo deformation (e.g., a concrete slab of a building that flexes or deforms), the deformation of the mounting surfaces impart similar deformations on the components of the measurement instruments, thereby producing measurement errors.
In addition, the conventional rigid mounting arrangement of force measurement devices frequently results in a deleterious preloading on these devices. This undesirable preloading may permanently deform various components of force measurement devices, which may also reduce the accuracy of the output generated by the force measurement systems.
What is needed, therefore, is a force measurement assembly that is isolated from the vibrations transferred from the surrounding building structure so that the measurement accuracy of the measurement instrument is not undesirably compromised. Moreover, a force measurement assembly is needed that is not subjected to unnecessary preload stresses that adversely affect the measurement components of the instrument. Furthermore, a force measurement system also is needed that includes a force measurement assembly that is sufficiently isolated from building vibrations so as to obviate the effect of these vibrations on the measurement accuracy of the force measurement assembly. In addition, a force measurement assembly is needed that is capable of compensating for undulations on the mounting surface, uneven portions of the mounting surface, and/or a deformation of the mounting surface.